In the Section "Investigating Life: Two Kingdoms and a Virus $\circ$

In the section "Investigating Life: Two Kingdoms and a Virus Team Up to Beat the Heat",what was the purpose of repeatedly drying,freezing,and thawing some of the fungi?

A) to kill the fungi
B) to prepare the fungi for growth at 65 ^$\circ$ C
C) to remove the virus
D) to prepare the fungi to infect the panic grass
E) to make the fungus more susceptible to the virus